This invention pertains to thermoplastic polyhydroxyether resins and more particularly to their conversion to water-borne resins.
Thermoplastic polyhydroxyether resins are a family of amorphous, high molecular weight phenoxy resins derived from diphenols and epichlorohydrin. They are noted for their excellent flexibility, impact and abrasion resistance and adhesive strength. Because of these outstanding properties, they are used commercially for a variety of coating and adhesive uses. In coating applications thermoplastic polyhydroxyethers also offer good salt-spray and overtake resistance.
Thermoplastic polyhydroxyethers are insoluble in water and are usually applied as a solution in organic solvents, such as, ketones or esters or mixture of such solvents. Because of their high molecular weight (at least about 20,000 weight average) and chain rigidity, a large amount of organic solvent must be employed to achieve a satisfactory solution properties during application. To prevent pollution of the atmosphere, environmental standards require that such organic solvents or vehicles must be either recovered or burned at considerable cost to the end user.
It is therefore an object of this invention to provide a means for employing thermoplastic polyhydroxyether resins without the use of large amouns of organic solvents.
It is another object of this invention to provide thermoplastic polyhydroxyethers which can be dispersed in water as water-borne compositions.
It is a further object of this invention to provide a system whereby thermoplastic polyhdroxyether resins can be applied and utilized from a water-borne system without significantly changing the desirable properties of the phenoxy resin.